Signal printing interlock mechanisms



April 26, 1960 c;. PEREZ SIGNAL PRINTING INTERLOCK MECBANISMS Filed May 13, 1957 ZSheets-Sheet 1 INVENTOR GUILLERMO P ATTORNEYS G. PEREZ SIGNAL PRINTING INTERLOCK MECHANISMS April 26, 1960 2,934,193

Filed May 13, 1957 2 Sheets-Sheet 2 .....,.....,.,.3 ws I a INVENTOR GUILLERMO PER Z ATTORNEYS United States Patent C SIGNAL PRINTING INTERLOCK MECHANISMS Guillermo Perez, Hartford, Conn., assignor to Royal McBee Corporation, Port Chester, N.Y., a corporation of New York Application May 13, 1957, Serial No. 658,666

1 Claim. (Cl. 197-5) This invention relates to an improved interlock mechanism for business machines and more particularly to a novel interlock-system for correlating the operation of the actuating mechanism for the printing and signalling devices of typewriters, telegraph printers and like machines.

In certain printing apparatus, such as the input typewriters used in data processing equipment, there is provided a plurality of electrical output signal means each of which is associated with one of the various type bars of the machine. As each of the respective type bars are successively actuated a corresponding electrical output signal is produced which is either stored or used to control other components of the data processing equipment. It is apparent that in such machines no more than one output signal should be produced at any one time and that any given signal so produced should always correspond to the same printed letter. Furthermore it is highly desirable that no signal be produced unless a letter or other figure is actually printed. Unless these conditions are met the electrical signal output may not always correspond to the printed record of the machine.

One object of the instant invention is to provide an eificient interlock mechanism for the various electrical signalling devices of a typewriter whereby no more than one output signal may be initiated at any one time.

Another object of the invention is to provide a simple means for permitting the initiation of a given output signal only when the related typebar partakes of its printing stroke.

A further object of the invention is to provide a means for insuring that a correct relation exists between the printing and signalling operations of a typewriter regardless of the type of drive mechanism used to actuate the various printing and signalling devices.

Other objects will become apparent as the disclosure progresses.

In the drawings:

Fig. 1 is a sectional view of the principal parts of a power-driven typewriter taken in a plane which is perpendicular to the main drive shaft of the machine and shows a related set of printing and signalling devices which are in their respective normal positions.

Fig. 2 is a side elevational view of a related set of printing and signalling devices and shows said devices in their respective active positions.

Fig. 3 is a detailed sectional View taken along line 3-3 of Fig. 2.

The drawings show the principal parts of a conventional electric typewriter and parts not necessary to an understanding of the instant invention have been omitted for the sake of clarity. It will be understood that unless otherwise indicated the various elements shown may be suitably mounted on the main frame of the machine in a manner well understood in the art.

Each typing action of the apparatus shown in Fig. 1 is initiated by depression of an operating key 2 which, through the linkage 3, comprising pivoted levers 4, 5 and 'ice 6, serves to release the spring biased driving pawl 8 for movement into engagement with the power driven snatch roll 9. The rotation of the snatch roll 9 causes the engaged pawl 8 to be displaced forwardly which, through link 10, rotates the bell crank or sub-lever 12 which is pivotally mounted on a cross shaft 13. This counterclockwise rotation of bell crank 12, as viewed in Figs. 1

and 2, will, through link 15, swing the pivotally supported type bar 16 in a clockwise direction so that the printing type 17 is impelled against the operative surface of the platen 18. This printing or typing action is of a conventional nature and need not be further explained here.

As shown in Figs. 1-3 there is provided a slotted ball retaining housing 20 which extends transversely of the typewriter frame. Housing 20 is preferably located to the rear of the normal complement of type bar actuating bell cranks 12 and is provided with a plurality of vertically disposed slots 21. The slots 21 are horizontally spaced so as to receive and guide the respective projections or extensions 22 formed on the bell cranks 12 and the longitudinal chamber 23 formed in said housing 20 is perpendicular to and communicates with said slots 21. A plurality of ball locking members 24 are movably disposed in said chamber 23. During the operative stroke of each of said bell cranks 12 the projections 22 pass upwardly through the respective slots 21 and enter said chamber 23 thereby laterally displacing the ball locking members 24 as shown in Fig. 3. The number and size of the members 24 used in said chamber 23 are such that at any one time there is sufiicient space between the ends 27 and 28 of chamber 23 for all of said ball locking members 24 and only one of said bell crank projections 22. By reason of this limitation, only one type bar 16 at a time may be displaced to printing position shown in Fig. 2.

The typewriter is further provided with an insulating block 30 which extends transversely of the machine and is secured by screws 31 to the rearwardly extending shoulder 32 of said housing 20. An electrically conductive contact plate 33 is attached by any suitable means to the lower surface of block 30. A plurality of electrically conductive spring contact members 34 are horizontally spaced and secured along the rearward edge of block 30 by means of the insulating clamp bar 35 and screws 36. Appropriate electrical wiring may be aflixed to said plate 33 and to the respective rearward ends of said members 34. As shown in Fig. 1 the forward ends of spring contact members 34 are normally spaced from the lower surface of contact plate 33. Integrally formed on each of said bell cranks 12 is a curved rearward extension 40 having fastened thereto an insulating tip 41. The bell crank tips 41 underlie and are normally spaced from their respective spring contact members 34 as shown in Fig. 1.

In the operation of the machine when any one of the type bars 16 is rotatably actuated to the printing position as above described, the tip 41 of the bell crank actuating said type bar will engage its associated spring contact member 34- and will move the latter into operative contact with the plate 33 as shown in Fig. 2, to thereby produce an electrical output signal which corresponds to the letter printed by said type bar 16. The operative surface 42 of each of said tips 41 is positioned so that contact between the spring member 34 and plate 33 is established only after the related bell crank projection 22 has entered the chamber 23 and has laterally disposed said members 24 to the locking position shown in Fig. 3; thus no output signal is produced unless a full printing stroke of the related type bar is etfected. Due to the operation of the ball interlock mechanism, it will be impossible to move more than one spring contact member 34 into engagement with the plate 33 at any one time. Likewise, it will be --2,9s4,1ss

impossible to print a given letter and at the same time initiate a disassociated electrical output signal. These functional conditions will be obtained when the bell cranks 12 are actuated either manually or by power means. The above described apparatus provides a reliable and inexpensive means for correlating the printing and signailing devices for a typewriter and insures that a true signal output is produced for each printing operation regardless of the speed of operation of the typewriter keys 2.

While there is in this application specifically described one form which the invention may assume in practice,

it will be understood that this form of the same is shown for purposes of illustration only and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claim.

The invention claimed is:

In a typewriter, a main frame, a plurality of type bars pivotally mounted on said frame, individual actuating means for each of said type bars, each of said actuating means including a pivotally mounted sub-lever, a ball interlock mechanism mounted on said frame adjacent said actuating means, a plurality of electrical switches supported on said frame, each one of said switches being associated with a different one of said sub-levers, a first extension formed on each one of said sub-levers and adapted to operate the related one of said switches, and a second extension formed on each one of said sub-levers and adapted to cooperate with said interlock mechanism for preventing the operation of more than one of said type bars at any one time, said extensions being relatively positioned on each of said sub-levers so that the first extension operates the associated switch only after the sec ond extension has operatively engaged said interlock mechanism whereby one and only one electrical output signal is initiated when any one of said type bars is operated.

References Cited in the file of this patent UNITED STATES PATENTS 523,617 Boughton July 24, 1894 1,996,013 Thompson Mar. 26, 1935 2,103,921 Thompson Dec. 28, 1937 2,816,609 Rossetto et al Dec. 17, 1957 2,874,369 Blain et a1. Feb. 17, 1959 

